11-o-methanesulfonylerythromycins

ABSTRACT

COVERS 11-0-METHANESULFONYLERYTHROMYCINS WHICH HAVE ANTIBIOTIC ACTIVITY.

United States Patent Ofice 3,816,398 Patented June 11., 1974 ABSTRACT OFTHE DISCLOSURE Covers 11-O-methanesulfonylerythromycins which haveantibiotic activity.

DESCRIPTION OF THE INVENTION (desosamine) cs, on,

"R (cladinose) ch, ecu,

(erythronolide) In this formula, when R R and R represent hydrogen and Rrepresents hydroxyl, the structure illustrated is erythromycin A. When Ris, however, also hydrogen, the structure of erythromycin B isillustrated. The term erythromycin when used herein without modificationis meant to embrace both forms, that is erythromycin A and erythromycinB.

Erythromycin, as will be noted from the formula, comprises three cyclicfragments. These fragments are referred to respectively as cladinose,desosamine and erythronolide. The positions on the cladinose ring areindiciated by double primed numbers; the positions on the desosaminering by single primed numbers; while positions on the erythronolide ringare indicated by unprimed numbers.

In order to prepare the erythromycin derivatives here one may start witheither erythromycin A or erythromycin B or the enol ethers of either.The enol ethers of erythromycin A and B and their preparation isdescribed in Kurath et al., Experientia 27, 362 (1971). The choice oferythromycin or its enol ether depends, of course, upon the particulardesired final product.

The first step in the invention is to protect the 2' and 4" positions oferythromycin. This is best accomplished by preparing the2'-()-acetyl-4-O-formyl derivative via the method outlined inco-pending, commonly assigned application bearing Ser. No. 119,418,filed Feb. 26, 1971, now US. Pat. No. 3,736,313.

The second step involves treating the above protected erythromycinderivatives with a methanesulfonating agent such as methanesulfonicanhydride or methanesulfonyl chloride usually carried out in an acidacceptor such as pyridine.

In order to form the hemiacetal of 11-O-methanesulfonylerythromycin Aone need only treat the 11-methanesulfonyl-2'-O-acetyl-4"-0-formy1erythromycin A with methanol. Atthe present time there is no evidence of formation of the correspondingerythromycin B hemiacetal.

In another sequence of reactions one may take erythromycin A, protectthe 2, 4" groups, form the enol ethers of the particular erythromycin A,and lastly form the methanesulfonyl derivative.

The following examples illustrates fully the preparation of thederivatives of the invention.

EXAMPLE I 11-O-Methanesulfonylerythromycin A 6,9-Hemiacetal A suspensionprepared from 14.4 g. of 2'-O-acetyl-4"- O-formylerythromycin A 7.3 g.of methanesulfonic anhydride, and 108 ml. of pyridine was stirred atroom temperature for 19 hours. The reaction mixture was shaken with amixture of 700 ml. of chloroform and 800 ml. of 5% NaHCO The chloroformsolution was washed four times with 600-ml. portions of water and driedover anhydrous magnesium sulfate. The chloroform was evaporated underreduced pressure and the residual pyridine was removed by azeotropiedistillation with benzene under reduced pressure to leave 15.1 g. ofII-O-methanesulfonyl- 2-O-acetyl- "-O-formylerythromycin A as a brownfoam.

A solution prepared from 2.1 g. of ll-methanesulfonyl-2'-O-acetyl-4"-O-formylerythromycin A and 50 ml. of methanol was allowedto stand at room temperature for four days. The major portion of themethanol was evaporated under reduced pressure, and the residue wasshaken with a mixture of 200 ml. of chloroform and 200 ml. of 5% NaHCOThe chloroform solution was washed with three ml. portions of water, anddried over anhydrous magnesium sulfate. Evaporation of the chloroformleft 1.54 g. of an orange glass.

The product thus obtained was chromatographed on a partitionchromatography column to yield 686 mg. of pure11-O-methanesulfonylerythromycin A 6,9-hemiacetal. IR: 3587, 3400-3550,1727 cm.- NMR: 6 3.29 (OCH 3.09 (0S0 CH 2.32 (NMez), 1.54 (C CH Theelemental analysis was in agreement with the empirical formula C H O NS.

EXAMPLE 2 11-0 Methanesulfonylerythromycin B A suspension prepared from7.5 g. of 2'-0-acetyl-4"- O-formylerythromycin B, 3.6 g. ofmethanesulfonic anhydride and 53 ml. of pyridine was stirred at roomtemperature for 17 hours. The reaction mixture was shaken with a mixtureof 400 ml. of chloroform and 400 ml. of 5% NaHCO The chloroform solutionwas washed with water, and dried over anhydrous magnesium sulfate.

Evaporation of the chloroform under reduced pressure and removal of theresidual pyridine by azeotropic distillation with benzene, under reducedpressure left 7.8 g. of 11 O methanesulfonyl 2' O acetyl 4" Oformylerythromycin B as a brown foam.

A solution prepared from 13 g. ofll-O-methanesulfonyl-2'-O-acety1-4"-O-formylerythromycin B in 350 ml. ofmethanol was allowed to stand at room temperature for four days. Theresulting solution was treated with Darco 6-60 and filtered through aceh'te mat. The filtrate was concentrated under reduced pressure, andthe residue was shaken with a mixture of 800 ml. of 5% NaHCO' and 700ml. of chloroform. The chloroform solution was washed with three 600-m1.portions of water and dried over anhydrous magnesium sulfate. Thechloroform was evaporated under reduced pressure at room temperature toyield 10.9 g. of a light-orange glass.

The product, thus obtained, (3.09 g.) was chromatographed on a partitionchromatography column to yield 320 mg. of pure11-O-methanesulfonylerythromycin B, as a white glass, IR: 3595, 3540,3400-3470, 1727, and 1704 cmr NMR: 6 3.31 (OCH 3.09 (OSO' CH 2.29 (NMeEXAMPLE 3 11-O-Methanesulfonylerythromycin A Enol Ether A solutionprepared from 15.5 g. of 2'-O-acetyl-4"-O- formylerythromycin A and 170ml. of glacial acetic acid was allowed to stand at room temperature for4 hours. The major portion of the acetic acid was evaporated underreduced pressure and the product, 2'-O-acetyl-4"- O-formylerythromycin Aenol ether (14 g.) was isolated by chloroform extraction as described inExample 1.

A suspension prepared from 2.0 g. of 2'-O-acetyl-4"-O-formylerythromycin A enol ether, prepared as described above, 20 ml. ofpyridine, and 1.0 g. of methanesulfonic anhydride was stirred at roomtemperature for 4 hours. The product, 11 Omethanesulfonyl-2'-O-acetyl-4"-O- formylerythromycin A (2.03 g.) wasisolated by chloroform extraction according to the procedure of Example1.

A suspension prepared from 2.0 g. ofII-O-methanesulfonyl-2-0-acetyl-4-O-formylerythromycin A, 50 ml. ofmethanol, and 5 ml. of 5% aqueous NaHCO was stirred at room temperaturefor 64 hours. The resulting solution was shaken with a mixture of ml. ofchloroform and 200 ml. of 5% NaHCO The chloroform solution was washedwith three 150 ml. portions of water and dried over anhydrous magnesiumsulfate. Evaporation of the chloroform left 1.8 g. of orange glass.Partition column chromatography of 1.7 g. of this product gave 681 mg.of pure l1-O=methanesulfonylerythromycin A enol ether, M.P. 122-131, [M-38; (OCH 3.17 (OSO CH 2.28 (NMe 1.58 (C CH3), 138 (C -CH The elementalanalysis was in agreement with the empirical formula C38H67O14NS.

EXAMPLE 4 1l-O-Methanesulfonylerythromycin B Enol Ether11-O-Methanesulfonylerythromycin B enol ether may be made from2'-O-acetyl-4"-O-formylerythromycin B via2'-O-acetyl-4"-O-formylerythromycin B enol ether.

The compounds were then tested for their activity against gram positiveand gram negative bacteria in an agar dilution test. Results are givenin agar dilution units. These may be converted to MIC values (minimuminhibitory concentrations) expressed in micrograms/ml. by merelydividing the agar dilution units into the concentration and multiplyingby the proper factor. Thus, for example, if one tested a sample at acencentration of 4 mg./ml., and determined it had an activity of 10 agardilution units, in order to determine the MIC value in micrograms/ml.one must divide the concentration of 4 by the number of agar dilutionunits, here 10, and multiply by 1000.

The compounds here were tested as to their activity against thefollowing organisms:

ECR =Multiple drug resistant Escherichia coli SF=Strept0c0ccus faecalisATCC 10541 PA =Pseudom0nas aeruginosa BMH #1 SA =Staphyl0c0ccus aureusATCC 643 SP Ec Escherichia coli ATCC 26 BS=Bacillus subtilis #10707(University of I11.) PV=Pr0teus vulgaris ATCC 6897 SS=Shigella sonneiATCC 9290 ST=Salm0nella typhosa ATCC 9992 KP=Klebsiella pneumoniae ATCC10031 Results are as follows:

TABLE I EOR SF PA SA EC BS PV SS ST KP Example I, 1 mgJml 0 640 0 320 0320 0 0 0 20 TABLE II EUR; SF PA SA EC BS PV SS ST KP Example 2, 1IngJml 10 20, 000 10 5, 000 10 20, 000 0 10 10 160 20 20 20 320 TABLEIII ECR; SF PA SA. EC BS .PV SS ST KP Example 3, 1 mg./ml 0 40 0 0 0 0 0The compounds were also tested against a variety of 4. The derivative ofclaim 1 which is II-O-methanesulother gram negauve and gram positivebacteria. Results fonylerythromycinA 6,9 enol ether. of ant bioticactivity are as follows. Figures are MIC 5. The derivative of claim 1which is II-O-methanevalues m terms of mcgJ-ml. Erythromycin B was usedas sulfonylerythromycin B 6,9-e001 ether. a standard. 5

TABLE IV Erythromycln Organism base Ex. 1 Ex. 2 Ex. 3

Staphylococcus aurcus 9144 2 50 3. 1 0 39 Staphylococcus aureus Smith- 02 50 3. 1 0 39 Staphylococcus ourcus Smith E 100 100 100 100Staphylococcus aurcu: Wise 155- 100 100 100 100 Streptococcus faccalis10541 0.05 6.2 0. 0 05 Escherichia colt Juhl 60 100 100 1,000) (1,000)Klebatello pncumontoc 10031 3. 1 25 6. 2 Proteus oulaoria Abbott 100 100100 1,000) 10,000) (1. Proteus mirabilis Finland #9 100 100 100 1, 000)1, 00) (1. Salmonella typhlmurium Ed #9 25 1,000) 1,000) Shtgellaao'n'nci 9290 12 100 100 12. 5 1 .m BMH 5o 100 100 50 1,000) (1,000)Sire, 1, Roper 100 100 100 100 Staphylococcus aureus Quinoes 100 100 100100 Sire, Str n Sco 0.2 100 100 100 Mucobacterium aollisepticum S6 0. 550 0. 5 0. 05 Mycobacterium arauularum 19108.. 100 1. 0 1 Mycobacteriu'mhuorhim'a 17981 0. 2 100 50 100 M, r tum FH 1.55 0.5 0.1 0.25Haemophi'lus iufluenzac Patterson 0. 78 100 12. 5 1. 56 Haemophiluaiufluc'nzae Brimm CSF 0. 78 50 3. 1 0. 78 Shemw 1. 50 50 3.1 1. 5oHaemophilua influcuzac Illinois 3. 1 100 12. 5 1. 56 I philus 4 Terry 1.56 50 6. 2 1. 56 Crithidio fascicalato 100 100 100 100 Trichomouasmgimlio CLMI 100 100 100 100 I 93.14 3.1 100 12.5 3.1

What is claimed is: References Cited 1. An erythromycin derivativeselected from the group v UNITED STATES PATENTS consisting ofl1-O-methanesfu1onylerythromycin A 6,9-

2,839,524 6/ 1958 Hemzelman et a1. 260-210 E hemiacetal,11-O-methanesulfonylerylthromycm B, 11-0 3 681 323 8/1972 Kur th t l 26210 E methanesulfonylerythromycin A 6,9 enol ether, and 11-0- a e a 0methanesulfonylerythromycin B 6,9 enol ether. JOHNNIE R. BROWN, PrimaryExaminer 2. The derivative of claim 1 which isII-O-methanesulfonylerythromycin A 6,9 hemiacetal. OWENS AssistantExaminer 3. The derivative of claim 1 which is II-O-methanesul- US. Cl.X.R. fonylerythromcyin B. 424-181

